1. Field of the Invention
This invention relates to a method of forming iridium- or iridium-containing materials on substrates, such as Ir-based electrode structures for microelectronic devices and subassemblies, as well as to Ir source reagent materials, and novel dielectric capacitor or ferroelectric material device structures.
2. Description of the Related Art
Iridium (Ir) and iridium oxide (IrO2) are of great interest for use as electrode materials in both dynamic random access memories (DRAMs) and for ferroelectric-based memory devices (FRAMs) which incorporate perovskite metal oxide thin-films as the capacitor layer.
The advantages of Ir over other possible electrode materials include ease of deposition, the ability to “dry etch” the material, the ability to form a stable conducting oxide at high temperatures in an oxidizing environment, and the ability to operate reliably at high temperatures in a working device.
The deposition and processing of Ir-based electrodes is highly desirable in view of the aforementioned advantages. Further, the formation of IrO2 acts as a diffusion barrier to oxidation of conducting polysilicon vias or plugs, as is required in high density DRAM or FRAM devices.
Based on the need for Ir-based electrodes, the art has continued to seek improvements in source materials and deposition techniques for the formation of Ir-based films.
The art has variously disclosed the chemical vapor deposition of iridium for the manufacture of electronic devices in a reducing atmosphere, such as hydrogen gas environment. The art has taught the use of such reducing atmosphere for the purpose of achieving the deposition of element metal iridium for electrodes in applications in which high temperature dielectric materials (e.g., SBT, BST, PZT, PLZT, PNZT, LaCaMnO3, etc., wherein SBT=strontium bismuth tantalate, BST=barium strontium titanate, PZT=lead zironium titanate, PLZT=lead lanthanum zirconium titanate, PNZT=lead niobium zirconium titanate) are deposited on the electrode, to minimize the possibility of degradation of the dielectric in such applications and to concurrently achieve the formation of high purity metal.
The art has especially sought improvements in process technology for the formation of semiconductor and ferroelectric structures that employ Ir electrodes specifically associated with complex dielectric or ferroelectric material layers as thin-film capacitors.
It is an object of the present invention to provide novel source reagents and a process for the formation of iridium-based electrodes that achieve a material simplification in fabrication efficiency and cost, and provide an electrode structure that is highly advantageous for integration with silicon device technology, being efficient, oxygen reactive, oxygen impermeable, and readily fabricated.
It is another object of the invention to provide a simplified method for the fabrication of metal oxide thin film capacitor structures including iridium, iridium oxide or iridium-containing electrode elements, as metal contacts for the oxide DRAM and FRAM devices.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.